Clinical Seminar, Left main stem angioplasty, 168001.
Austria, Vienna, 3 September 2007:
The left main coronary artery supplies at least two thirds of the hearts blood supply. When it becomes narrowed it causes large areas of the heart to malfunction with subsequent severe anginal chest pain and breathlessness. Occlusion of the left main coronary is usually fatal within a matter of seconds. Recent improvements in stent technology have allowed successful treatment of this immediately life threatening condition. Results are sufficiently encouraging to challenge the traditional role of surgery and consider stenting as an alternative
Surgical bypass has been the mainstay of treatment for left main coronary narrowings for many years. Bypass has a proven track record of prolonging life and reducing symptoms. Initial attempts at balloon dilation for treatment of left main disease yielded poor results with a procedural risk of death of 10% and a 3 year mortality of >60%. These results were not particularly improved by the introduction of stents and procedural risk appeared to remain >10%.
Improved stent technology has reduced restenosis and increasing expertise in implantation technique has resulted in sequential improvement in results. In Oxford, we began using stents in sick elderly patients presenting with left main disease 10 years ago. Most of these patients were unsuitable for surgery. Patients tolerated the procedure well and procedural results were encouraging. Subsequently we have successful used stents in many emergency and urgent situations. More recently we have used newer drug eluting stents in these patients.
Review of our Oxford data between April 2001 and October 2005 in 100 patients shows the outcomes for the three distinct patient groups. At long-term follow-up 651±431 days (range 6-1741) patients presenting for emergency PCI had a 72% survival rate, non-surgical candidates had 83% survival and the patient/physician preference group had a 100% long-term survival. Despite 72/100 patients in our study being either non-surgical candidates or presenting with complicated acute infarction, these data shows good short and long-term results from PCI treatment of left main disease. Those patients that were potentially suitable for surgery had very good outcomes and the numbers of left main procedures in our cath lab continues to rise.
These results are similar to data emerging from other centres around the world. A series using drug eluting stents in 150 pts with relatively simple disease of the ostium or shaft of the left main has shown excellent result in >90% patients at nearly 3 years with a very low mortality. Recently a randomised trial has confirmed that drug eluting stents are better than non coated bare metal stents. In this series the 6 month mortality was only 2%. Historical comparisons with UK surgical databases suggest the surgical risk at 30 days post-operative in this group may be 3.5%. Rates of drug eluting stent late thrombosis in the left main are minimal although numbers are relatively small and follow up is incomplete in some studies.
Consequently randomised comparisons with surgical revascularisation have been recruited. A small study (105 patients) has suggested that stent treatment and surgery may be equivalent for left main disease and subsequently a worldwide larger study with 500 patients has been recruited - the Syntax le Mans trial.
It is clear that stents can be used for left main disease in emergency and urgent situations when surgery cannot be considered. Under these circumstances, stents are life saving. Carefully deployed drug eluting stents probably have a role in elective patients with uncomplicated left main disease. Completion of randomised trials will show whether stenting with drug eluting stents can now be considered an equivalent therapy to surgery in this challenging patient group.